Heat pipe with ultra-thin flat wick structure

ABSTRACT

A heat pipe with an ultra-thin flat wick structure includes a shell and a wick structure disposed in the shell. The wick structure includes heat exchange zones and at least one liquid channel connected between the heat exchange zones which are divided into an evaporation portion and a condensation portion. Each of the heat exchange zones has a plane and a pressing surface opposite to the plane. A plurality of elongated concave surfaces are spacedly arranged on the pressing surface such that a respective steam channel is formed via each of the concave surfaces in the shell and a respective elongated wick structure connection is formed between each concave surface and the plane. Cut-out zones are formed at two sides of the liquid channel between the heat exchange zones in the shell.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to an ultra-thin plate type heat pipe and in particular to a heat pipe with an ultra-thin flat wick structure.

2. Description of Related Art

Since most current 3C electronic products indicate a trend towards a light, thin, short, and compact design, the heat pipes used therein for heat dissipation or heat conduction also need to be thinned down, which causes the creation of the ultra-thin plate type heat pipe (the thickness is below about 1.5 mm).

However, the thickness of the ultra-thin plate type heat pipe needs to be thinned, thus resulting in a thinner thickness of the wick structure therein, otherwise the steam channels with sufficient space cannot be formed in the heat pipe. During the manufacturing process, the excessively thin wick structure cannot be filled through the gap between the wall of the heat pipe and the mandrel. The reason is that a relatively small gap causes a greater resistance when the metal powder is filled and thus cannot be processed subsequently. Therefore, the powder wick structure in the previous ultra-thin plate type heat pipe is formed only in the local area in the heat pipe and not thinned. Consequently, the powder wick structure in the ultra-thin plate type heat pipe of the prior art cannot be easily filled into the cross section of the heat pipe completely, which cannot provide the adequate surfaces for evaporation and condensation and the truncated transfer surface. Also, this still does not have sufficient steam channels and solid internal support structures, resulting in easy collapse of the heat pipe and thus greater thermal contact resistance. Hence, the heat transfer efficiency cannot be improved further.

In view of this, the inventor pays special attention to research with the application of related theory and tries to overcome the above disadvantages. Finally, the inventor proposes the present invention which is a reasonable design and effectively overcomes the above disadvantages.

SUMMARY OF THE INVENTION

The main objective of the present invention is to provide a heat pipe with an ultra-thin flat wick structure, in which the thinned wick structure can be formed on the inner wall of the heat pipe such that the steam channels can be maintained to provide sufficient space for heat transfer by evaporation and condensation after the ultra-thin heat pipe is pressed and formed, to provide the maximal capillary surface area and truncated transfer surface, and to provide more solid internal support structures to make the heat pipe not easy to collapse and have lower thermal contact resistance, achieving the objective of providing an ultra-thin heat pipe.

To achieve the above objective, the present invention provides a heat pipe with an ultra-thin flat wick structure, comprising a hollow shell having a flat shape, and a wick structure disposed in the shell. The wick structure comprises a plurality of heat exchange zones and at least one liquid channel connected between the heat exchange zones. The heat exchange zones are divided into at least one evaporation portion and at least one condensation portion. Each of the heat exchange zones has a plane and a pressing surface opposite to the plane. The plane is attached to an inner wall of the shell. A plurality of elongated concave surfaces are spacedly arranged on the pressing surface such that a respective steam channel is formed in the shell via each of the concave surfaces and a respective elongated wick structure connection is formed between each concave surface and the plane. Cut-out zones are formed at two sides of the liquid channel between the heat exchange zones in the shell.

BRIEF DESCRIPTION OF DRAWING

FIG. 1 is a perspective schematic view of the present invention;

FIG. 2 is a cross-sectional schematic view along line 2-2 of FIG. 1;

FIG. 3 is a local perspective schematic view of the wick structure of the present invention;

FIG. 4 is a cross-sectional schematic view of the wick structure according to the second embodiment of the present invention;

FIG. 5 is a cross-sectional schematic view of the wick structure according to the third embodiment of the present invention;

FIG. 6 is a cross-sectional schematic view of the wick structure according to the fourth embodiment of the present invention;

FIG. 7 is a cross-sectional schematic view of another embodiment of the present invention along a longitudinal direction thereof;

FIG. 8 is a perspective schematic view of the wick structure according to the fifth embodiment of the present invention;

FIG. 9 is a perspective schematic view of the wick structure according to the sixth embodiment of the present invention; and

FIG. 10 is a cross-sectional schematic view according to another embodiment of the present invention.

DETAILED DESCRIPTION OF THE INVENTION

To make examiners understand the features and technical contents regarding the present invention, please refer to the following detailed description and attached figures. However, the attached figures are only used for reference and explanation, not to limit the present invention.

Please refer to FIG. 1, which is a perspective schematic view of the present invention. The present invention provides a heat pipe with an ultra-thin flat wick structure, which comprises a hollow shell 1 having a flat shape and at least one wick structure 2 disposed in the shell 1 and contacted with an inner wall of the shell 1.

As shown in FIGS. 1 and 2, the shell 1 may be formed to have the flat shape by manufacturing processes such as pressing. The thickness T of the external contour of the shell 1 may be formed below 0.5 mm by pressing. In the embodiment of the present invention, after the shell 1 is pressed, it has an upper wall 10, a lower wall 11, and side edges 12 surrounding the outer edges of the upper wall 10 and the lower wall 11.

Please refer to FIGS. 2 and 3. The wick structure 2 is disposed in the shell 1 and comprises a plurality of heat exchange zones 20 and at least one liquid channel 21 connected between the heat exchange zones 20. The wick structure 2 may be braid, fiber, sintered metal powder, or any combination thereof to form the above-mentioned shape. The heat exchange zones 20 are divided into at least one evaporation portion and at least one condensation portion. Each heat exchange zone 20 has a plane 200 attached to an inner wall 110 of the shell 1 and a pressing surface 201 attached to another inner wall 100 of the shell 1. A plurality of elongated concave surfaces 202 are evenly or unevenly spacedly arranged on the pressing surface 201 by pressing. The concave surfaces 202 are extended and disposed along a longitudinal direction of the wick structure 2 such that a respective steam channel 101 is formed in the shell 1 via each of the concave surfaces 202.

Also, a respective elongated wick structure connection 203 is formed between each concave surface 202 and the plane 200 of the wick structure 2. Cut-out zones 102 are formed at two sides of the liquid channel 21 between the heat exchange zones 20 in the shell 1. The cut-out zones 102 can be used as low flow resistance zones which increase the flowing area for working fluid during vapor-liquid phase change. Furthermore, the thickness t1 of the wick structure 2 is below about 0.25 mm and the minimum thickness t2 of each elongated wick structure connection 203 ranges about from 0.02 mm to 0.04 mm.

Further, as shown in FIG. 2, each of the concave surfaces 202 may have a shape of an arc; as also shown in FIGS. 4-6, each concave surface 202 many have a shape of an “V”, a rectangle, or a trapezoid. As shown in FIG. 7, viewed cross-sectionally along a longitudinal direction of the wick structure 2, each concave surface 202 gradually expands or shrinks along a longitudinal direction of the wick structure 2.

In addition, as shown in FIG. 8, the concave surface 202 of each heat exchange zone 20 of the wick structure 2 of the present invention may have penetrated heat transfer holes 204 to enhance heat transfer. Also, as shown in FIG. 9, a plurality of recesses 205 may be recessed and disposed between the respective concave surfaces 202 by the above-mentioned pressing such that after the wick structure 2 is placed into the shell 1, the adjacent formed steam channels 101 can communicate with each other.

Moreover, as shown in FIG. 10, the present invention further comprises another wick structure 2 such that the two above-mentioned wick structures 2 are stacked up and down with respective heat exchange zones 20 and the concave surfaces 202 on the opposite heat exchange zones 20 are up-and-down corresponding to each other to form the steam channels 101 via the concave surfaces 202 of the two above-mentioned wick structures 2.

In summary, the present invention indeed achieves the expected objective and overcomes the disadvantages of the prior art. In addition, the present invention is useful, novel and non-obvious, which meets the requirements of patent application. Please examine the application carefully and grant it a patent for protecting the rights of the inventor.

The embodiments described above are only preferred ones and not to limit the scope of appending claims regarding the present invention. Therefore, all the modifications of equivalent technology and means which apply the specification and figures of the present invention are embraced by the scope of the present invention. 

What is claimed is:
 1. A heat pipe with an ultra-thin flat wick structure (2), comprising: a hollow shell (1) having a flat shape; and a wick structure (2) disposed in the shell (1), the wick structure (2) comprising a plurality of heat exchange zones (20) and at least one liquid channel (21) connected between the heat exchange zones (20) divided into at least one evaporation portion and at least one condensation portion, wherein each of the heat exchange zones (20) has a plane (200) and a pressing surface (201) opposite to the plane (200), wherein the plane (200) is attached to an inner wall (110) of the shell (1), wherein a plurality of elongated concave surfaces (202) are spacedly arranged on the pressing surface (201) such that a respective steam channel (101) is formed in the shell (1) via each of the concave surfaces (202) and a respective elongated wick structure connection (203) is formed between each concave surface (202) and the plane (200), wherein cut-out zones (102) are formed at two sides of the liquid channel (21) between the heat exchange zones (20) in the shell (1).
 2. The heat pipe according to claim 1, wherein the shell (1) further comprises another wick structure (2) such that the two wick structures (2) are stacked up and down with respective heat exchange zones (20) and the concave surfaces (202) on the opposite heat exchange zones (20) are up-and-down corresponding to each other to form the steam channels (101).
 3. The heat pipe according to claim 1, wherein an external contour of the shell (1) has a thickness below 0.5 mm.
 4. The heat pipe according to claim 1, wherein each heat exchange zone (20) of the wick structure (2) has penetrated heat transfer holes (203) on the concave surfaces (202) thereof
 5. The heat pipe according to claim 1, wherein a plurality of recesses (205) are recessed and disposed on each concave surface (202) of each heat exchange zone (20) of the wick structure (2) to make the adjacent steam channels (101) communicate with each other.
 6. The heat pipe according to claim 1, wherein each concave surface (202) of each heat exchange zone (20) of the wick structure (2) has a shape of a “V”, an arc, a rectangle, or a trapezoid.
 7. The heat pipe according to claim 1, wherein each concave surface (202) gradually expands or shrinks along a longitudinal direction of the wick structure (2).
 8. The heat pipe according to claim 1, wherein each concave surface (202) is extended and disposed along a longitudinal direction of the wick structure (2).
 9. The heat pipe according to claim 1, wherein a thickness of the wick structure (2) is below 0.25 mm.
 10. The heat pipe according to claim 9, wherein a minimum thickness of the respective elongated wick structure connection (203) ranges from 0.02 mm to 0.04 mm.
 11. The heat pipe according to claim 10, wherein the shell (1) has an upper wall (10), a lower wall (11) spaced with and opposite to the upper wall (10), and side edges (12) surrounding the outer edges of the upper wall (10) and the lower wall (11).
 12. The heat pipe according to claim 11, wherein the wick structure (2) is braid, fiber, sintered metal powder, or any combination thereof 